title: You are what you talk: quorum sensing induces individual morphologies and cell division modes in Dinoroseobacter shibae.
abstract: Dinoroseobacter shibae, a member of the Roseobacter clade abundant in marine environments, is characterized by a pronounced pleomorphism. Cell shapes range from variable-sized ovoid rods to long filaments with a high copy number of chromosomes. Time-lapse microscopy shows cells dividing either by binary fission or by budding from the cell poles. Here we demonstrate that this morphological heterogeneity is induced by quorum sensing (QS). D. shibae utilizes three acylated homoserine lactone (AHL) synthases (luxI1-3) to produce AHLs with unsaturated C18 side chains. A ΔluxI1-knockout strain completely lacking AHL biosynthesis was uniform in morphology and divided by binary fission only. Transcriptome analysis revealed that expression of genes responsible for control of cell division was reduced in this strain, providing the link between QS and the observed phenotype. In addition, flagellar biosynthesis and type IV secretion system (T4SS) were downregulated. The wild-type phenotype and gene expression could be restored through addition of synthetic C18-AHLs. Their effectiveness was dependent on the number of double bonds in the acyl side chain and the regulated trait. The wild-type expression level of T4SS genes was fully restored even by an AHL with a saturated C18 side chain that has not been detected in D. shibae. QS induces phenotypic individualization of D. shibae cells rather than coordinating the population. This strategy might be beneficial in unpredictably changing environments, for example, during algal blooms when resource competition and grazing exert fluctuating selective pressures. A specific response towards non-native AHLs might provide D. shibae with the capacity for complex interspecies communication.
authors.affiliation: Helmholtz-Centre for Infection Research (HZI), Braunschweig, Germany.
authors.forename: Diana
authors.initials: D
authors.lastname: Patzelt
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Ina
authors.initials: I
authors.lastname: Buchholz
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.forename: Lothar
authors.initials: L
authors.lastname: Gröbe
authors.forename: Silke
authors.initials: S
authors.lastname: Pradella
authors.forename: Alexander
authors.initials: A
authors.lastname: Neumann
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulz
authors.forename: Steffi
authors.initials: S
authors.lastname: Heyber
authors.forename: Karin
authors.initials: K
authors.lastname: Münch
authors.forename: Richard
authors.initials: R
authors.lastname: Münch
authors.forename: Dieter
authors.initials: D
authors.lastname: Jahn
authors.forename: Irene
authors.initials: I
authors.lastname: Wagner-Döbler
authors.forename: Jürgen
authors.initials: J
authors.lastname: Tomasch
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D009154:Mutation; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology*; D041902:Rhodobacteraceae / Q000166:cytology* / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D054742:Acyl-Butyrolactones